Latch



R. MARPLE June 5, 1934.

LATCH Filed Dec. 16. 1929 lli-E. I lun-...

Inver FOM@ Wam/vila, gw/O JW Patented June 5, 1934 UNITED STATES PATET oFFicE LATCH poration or Michigan Application December 16, 1929, Serial No. 414,269

6 Claims.

The present invention relates to improvements in latches, and has particular reference to latches of the spring pressed, hand lever actuated type of the character commonly employed on vehicle doors.

It is a matter of common experience that a progressively increasing resistance must be overcome in turning the operating handle of a spring pressed automobile door latch, from its normal or locked position, in which the latch bolt is projected, to its open position, in which the latch bolt is retracted. The resistance to be overcome is augmented by the fact that even when the latch is in its extreme projected position the latch actuating spring must be under sufficient tension to strongly urge the bolt outwardly.

This characteristic of spring actuated latch devices has been a source of great annoyance and inconvenience and its elimination through the reduction of spring sizes has been prevented because of the possibility of thereby impairing the reliability of the lock.

It is accordingly the primary object of this invention to provide a new and improved latch of the above type in which the bolt may be retracted by the application of a substantially uniform and constant pressure upon the operating handle.

Another object of the invention is to provide a novel door latch in which the moving parts may be rigidly secured in locked position through the interpositioning of a cam actuated dog.

Still another object is to provide a new and improved latch of the above type which is simple, inexpensive, and capable of easy and certain operation.

Further objects and advantages will become apparent as the description proceeds.

Figure 1 is an inside view in elevation of a latch embodying a preferred form of the invention, the parts being shown in locked position.

Fig. 2 is a view similar to Fig. 1 with the parts in unlocked position.

Fig. 3 is a horizontal sectional View taken along line 3-3 of Fig. 1.

Fig. 4 is a horizontal sectional View taken along line 4 4 of Fig. 1.

Fig. 5 is a vertical sectional view taken along line 5--5 of Fig. 2.

While the invention is susceptible of various modifications and alternative constructions, I have shown in the drawing and will herein describe in detail the preferred embodiment, but it is to be understood that I do not thereby intend to limit the invention to the speciiic form disclosed but intend to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring more particularly to the drawing, the latch constituting the exemplary embodiment of the invention comprises a base plate 10 and a side flange 11 substantially normal thereto and having a bolt aperture 12. The latch is adapted to be mounted in a recess formed in the inner face of a vehicle door (not shown) and rigidly supported thereon by fastening means adapted to be received by holes 13 provided in the base 10.

Slidably mounted upon the base 10 is a latch assembly 14, including in the present instance a bolt 15 projecting outwardly through the aperture l2 for engagement with a lock strike (not shown).

Rigidly secured to the end of the bolt 15 is an inwardly extending irregularly shaped guide member 16 (see Fig. 3). In the present instance, the guide member 16 is translatably supported adjacent its inner end by a section 19 of the base 10 which is turned forwardly and then inwardly to define a bearing 18, the inwardly extending portion providing lateral bearing surface for the guide.

The guide member 16 partially overlies a flat coil spring 20 which is removably mounted on the base plate 10 and which in the present ernbodiment of the invention is slidably anchored at its inner en d between the lug 17 and an opposed lug 21 struck forwardly from the plate. The free end of the spring 20 engages a lug 22 struck rearwardly from the guide member 16, substantially in the longitudinal axis thereof, and tends to urge the associated bolt 15 outwardly through aperture 12 into projected position.

To operate the bolt from a position externally of the door (not shown), mechanism is provided which is effective as an incident to its operation, under the iniiuence of a substantially uniform pressure, to exert a force to retract said bolt, which increases in magnitude by increments substantially equivalent to the progressively increasing resistance with which the spring resists progressive deformation. In this instance, such mechanism comprises a normally vertical lever 23 pivotally mounted upon the base 10 and adapted tobe rotated by a'spindle 24. The outer end of lever 23 is formed with a shoulder 25 adapted to abut the ilange 11 to limit the movement of the lever in a counterclockwise direction as viewed in Figs. 1 and 2. Coacting with the lever 23 is a compression link 26 of which one end is pivoted to the former part at 27 and the other end is rounded and seated for pivotal movement in a socket recess 28 deiined by an upstanding lug 29 on the guide member 16. Thelever 23 is normally urged in a counterclockwise direction to the position occupied in Figs. 1 and 2 by means comprising in the present instance a flat coiled V'spring 30 whose inner end is removably mounted between two upstanding lugs 31 struck forwardly from the base. The free end of spring 30 operatively engages an arcuately formed section 32 on the inner vertical edge of the lever 23 adjacent its free end.

A cover plate Q3 having an aperture 34, formed concentric with the pivotal axis of lever 23, overlies the lever as well as part of the link 26 and likewise serves to partially cover the spring 3G. The cover plate 33 is maintained in spaced relation to the base 10 by lugs 35 formed integrally therewith and struck outwardly to abut the base. Outwardly extending tongues 36 formed on the lugs 35 pass through suitable slots 37 in the base and are bent into Contact with its outer surface to secure the cover plate in position.

The latch is rendered operable from the interior of the door (not shown) by the action of a member which is independent of the external actuating means, and which in addition functions as one element of the locking means, and provides a lateral bearing for the link 26. 'I'o this end, an elongated bar 38 is slidably connected to the member 16 by means of a headed stud 39 on the upstanding lug 29 engaging an elongated horizontally disposed slot 40 formed in the bar.

For purposes of convenience in assembling the latch, which is normally in the position shown in Fig. 2, the slot 40 is enlarged at its inner end to pass over the head of the stud. The inner end of the bar 36 is supported in a guide bearing 4l provided in this instance by the forward and inwardly turned section 19 of the base 10.

The invention contemplates the provision of locking means effective to block the bolt in its projected or outward position which shall be positively moved into and out of operative position without the use of springs. In furtherance of this end a dog 42 is pivotally mounted on the base l0 at 43. A toe 44 is rigidly secured to and extends laterally of an arm 45 of the dog 42 and projects radially somewhat beyond the end thereof.

The plate 44 is adapted to be rotated from an inoperative position as viewed in Fig. 2 to an operative position as shown in Fig. 1 in which it rests in proximity to a heel 46 formed on the upper edge of the link 26.

To effect economy of parts and simplicity of construction, the inner actuating bar 38 is so formed as to effect a positive movement of the dog 42. To this end the upper edge of bar 38 is provided with cam surfaces 47 and 48 which are in the plane of, and adapted to contact, surfaces 49 and 50 respectively on the opposed arms of the dog.

The relationship between the cam surfaces 47 and 48 is such that one or the other is normally in engagement with its respective coacting surface on the arms of the dog.

In operation, the lever 23 is rotated in a clockwise direction (as viewed in Fig. l) by means of a handle not shown) attached to the spindle 24. The link 26 is thereby moved inwardly and its abutting contact with lug 29 serves to move the member 16 and its associated bolt 15 inwardly against the action of springs 2U and 30.

Upon initiating the movement to retract the bolt the springs resist the turning effort with a leverage which is equivalent substantially to the distance from the plane of the axis of the lever to the plane of the axis of the pivotal connection between the lever and link. As the pivotal point common to the link and lever rotates from the position shown in Figs. l and 2 the vertical distance between the piane of its axis and the plane of the axis of rotation of the lever constantly diminishes and the effectiveness of the resistance of the springs is correspondingly decreased. The decrease in eiective resistance by the springs is ofset, however, by 'their previously discussed characteristic of resisting progressive deformation with progressively increasing force.

Thus the preferential leverage thereby afforded the operative serves to negative the normal action of the spring to resist with increasing force as the bolt is retracted.

When the bar 3S is moved to the left as viewed in Fig. 2, the cam surface 47 contacts the surface 49 and the dog 42 is rotated counterclockwise until the plate 44 moves downward into blocking relation with the heel 46. It will be evident that with the dog in this position the link 26 Will be prevented from moving inwardly to retract the latch. Similarly when the bar 38 is moved to the right or inwardly the surface 48 contacts the surface 50 to rotate the dog 42 in a clockwise direction out of blocking position with the link 26.

The bar 3S likewise serves to retract the latch directly against the action of spring 20 independently of the remaining mechanism of the latch.

Thus it will be apparent that a latch structure has been provided in which the bolt may be retracted by the application of a substantially uniform pressure to the actuating member and the bolt may be positively locked in its projected position without the use of springs.

I claim as my invention:

l. A vehicle door latch comprising, in combination, a base, a bolt movably mounted on said base, a spring urging said bolt outwardly, externally operable actuating means for moving said bolt inwardly against the action of said spring, said means comprising a lever pivoted to said base and a link pivoted on said lever, the free end of said link having an abutting connection with said bolt to retract said bolt against the action of said spring, said connection permitting movement of said bolt in a reverse direction independently of said link, a dog pvotally mounted on said base and having a locking abutment, a second locking abutment on said link, said abutnients being movable into locking relation to restrain said link from retracting said bolt, an elongated member having a pin and slot connection with said bolt permitting inward movement of said member to retract said bolt and outward movement relative to said bolt, cam means on said member in operative engagement with said dog to move said abutments into locking relation when said member is in its outward position.

2. A latch lfor vehicle doors comprising, in combination, a base, a bolt movably mounted on said base, a spring urging said bolt outwardly, an externally operable toggle to retract said bolt against the action of said spring, an internal actuator to retract said bolt against the action of said spring and constructed to permit independent retraction of the bolt and cam means operated by said internal actuator to lock said toggle against actuation of said bolt with the latter in its outward position.

3. A latch for vehicle doors comprising, in combination, a base, a boit movably mounted on said base, a spring acting on said bolt to project the latter outwardly, an outside operator in cluding a lever pivotally mounted on said base, a link pivoted on said lever and adapted to engage with said bolt, said lever and said link being operable to move said bolt from projected to retracted position, an inside operator, and cam actuated means mounted on said base and operable by the inside operator to lock said link against actuation by said lever with said bolt in projected position.

4. A latch for vehicle doors comprising, in combination, a base, a bolt movably mounted on said base, a spring acting on said bolt to project the latter outwardly, a manually operable lever pivotally mounted on said base, a link pivoted on said lever and in operative engagement with said bolt, said lever and link being operable to move said bolt against the action of said spring, a second means to actuate said bolt against the action of said spring, a dog pivotally mounted on said base and adapted to be interposed in the path of said link to lock said bolt against actuation by said link, and a cam slid` ably mounted on said base for moving said dog at will into and out of locking position, said cam being moved out of locking position as an incident to movement of said second means to actuate said bolt.

5. A door latch comprising a back plate, a tensioned bolt movable in the plane of said back plate, link means for retracting said bolt having lost motion in a reverse direction when said bolt is in projected position, a roll back for retracting said bolt independently of said link means, a member interposed between said bolt and roll back and movable with the latter when the bolt is moved into its retracted position, pivotally mounted blocking means carried by said back plate, and cam means operable in the movement of said link` means positively to move said blocking means both into and out of the path of movement of said member thereby to control actuation of the roll back.

6. A latch for vehicle doors comprising, in combination, a base, a bolt movably mounted on said base, a spring urging said bolt outwardly, an outside actuator comprising a roll back, a member' in abutting relation to said bolt and operable by said roll back in a direction to retract the bolt While permitting independent movement of the bolt, an inside actuator arranged for engagement with the bolt to retract itrbut movable independently thereof in a non-retracting direction, a dog pivoted on said base, and means including a cam operable in such independent movement of the inside actuator in a non-retracting direction positively to move said dog into blocking relation to said member to prevent retraction of the bolt by the outside actuator, said cam means being operable upon return of said inside actuator positively to move said dog out of blocking relation.

ROLLO MARPLE. 

